In the prior art, cylinder position sensing devices may use a magnet embedded in a piston and one or more Hall effect sensors that sense the magnetic field; hence, relative displacement of the piston. However, in practice such cylinder position sensors are restricted to cylinders with limited stroke and may require expensive magnets with strong magnetic properties. Other prior art cylinder position sensing devices may use magnetostrictive sensors which require multiple magnets to be mounted in the cylinder. To the extent that machining and other labor is required to prepare for mounting of the magnets, the prior art cylinder position sensing may be too costly and impractical for incorporation into certain shafts. Thus, a need exists for a reliable and economic technique for determining the position of a piston or other member.